• Journal of the Korean Chemical Society
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• v.39 no.11
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• pp.848-855
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• 1995

The influence of gravitational effect on the retention behaviors of polystyrene (PS) and polymethylmethacrylate (PMMA) in flat type thermal field flow fractionation (Thermal FFF) was studied. In the case of downward flow of mobile phase, the gravitational effect acting in the same direction of mobile phase flow increases as the angle of the system from the horizontal line (0˚to 60˚) increases. The decreasement of retention time of PS & PMMA was found. Also, the increasement of dimensionless λ values was found. And the difference in the retention time of PS & PMMA having different molecular weight decreases and also the resolution decreases. In the case of upward flow of mobile phase, the gravitational effect acting in the opposite direction of mobile phase flow increases as the angle of the system from the horizontal line (0˚to 60˚) increases. The increasement of retention time of PS & PMMA was found. Also, the decreasement of dimensionless λ values was found. And the difference in the retention time of PS & PMMA having different molecular weight increases and also the resolution increases.

• 월간산업보건
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• s.285
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• pp.41-53
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• 2012

• Analytical Science and Technology
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• v.7 no.3
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• pp.329-338
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• 1994

The retention behaviors of natural gas components were studied on a single column by gas chromatography. The dead time, $t_0$ was obtained by using extrapolation of homologous series to determine capacity factors. The plots of retention data for homologous series and carbon number at different temperatures were shown to converge into a single point, which point was determined as a dead time. The results of the effect of temperature on the column efficiency for n-butane exhibited the plate number, N incerased with temperature, but the resolution among the fast eluted components decreased. The adsorption enthalpy (${\Delta}H^0{_{ads}}$) for each component on 28% DC 200 stationary phase was determined, and in order to investigate the retention behaviors of natural gas components the regression analysis of log $t_R$, log k' and log ${\alpha}$ vs. van der Waals volume(Vw), molecular connectivity index(X) and hydrophobic fragmental constant(f) were carred out. Good correlation was found between log k' vs. Vw, and log k' vs. f. The correlations between the physical properties of natural gas and the physical parameters were investigated by the linear regression analysis. The relationships between Vw vs. molecular weight and heating value(${\Delta}H_{comb}$), X vs. boiling point, and f vs. molecular weight, boiling point and heating value exhibited the high correlation coefficient more than 0.99. Using the regression equation between the heating value of natural gas and Vw the predicted heating values from $C_6$ to $C_{10}$ showed good agreement with those reported in the literature within 0.2% relative error.

• Analytical Science and Technology
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• v.25 no.4
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• pp.207-213
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• 2012

Analysis of the aroma constituents present in the rose essential oil of Chinese Kushui type (Rosa sertata ${\times}$ Rosa rugosa) by GC-FID and GC-MS was performed independently as an expert for the inter-laboratory round-robin test to verify reproducibility according to the decision of the preliminary meeting of ISO/TC-54 (Shanghai, Sep. 14-15, 2010). Total 179 peaks (using SPB-1 apolar column), 165 peaks (using DB-624 intermediate polar column), and 162 peaks (using Supelcowax-10 polar column) were separated by GC-FID, respectively. Major constituents (over 5%) by GC-FID were ${\beta}$-citronellol (41.6~46.7%), geraniol (9.7~11.0%), and nerol (3.4~4.5%). ${\beta}$-Citronellol peak was overlapped with nerol peak on SPB-1 and DB-624 columns, whereas the two peaks were separated each other on Supelcowax-10 column. Our results were generally consistent with Chinese data (ISO/DIS 25175); however, a peak of phenethyl alcohol separated by using PEG (Supelco wax) column was found at the quite different retention time. Comparative analysis was conducted using Bulgarian rose (Rosa damascena Miller) oil and perfume. Bulgarian rose oil showed rich amounts of characteristic aroma constituents than the essential oil of Chinese Kushui type.

• Journal of the Korean Chemical Society
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• v.38 no.9
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• pp.640-652
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• 1994

This work is undertaken to determine alcohol homologues so-called fusel oil that may be present in the Korean folk sojues (distilled liquor) made from grains and to describe sample preparation and analytical method by GC-FID-MS. Solid phase extraction method for sample preparation by using porous styrene divinyl benzene polymer (Porapak Q) was compared with steam distillation and solvent extraction method. Retention behaviors of homologous series of alcohols were also studied. Log values of retention time, molecular weight, boiling point, and capacity factor of alcohols showed linear correlations to the carbon number of an alcohol, to the oven temperature, and to the dielectric constant. Components such as methyl alcohol, n-propyl alcohol, isobutyl alcohol, isopentyl alcohol, and phenethyl alcohol have been identified. The more amount of isopentyl alcohol than other alcohols are contained in the Korean folk sojues, while that of n-propyl alcohol are contained in Chinese kaoliangchiew. Degree of similarity or dissimilarity and classification of the individual samples were discussed using multivariate statistical analysis(principal components analysis) based on GC data.

• Research in Plant Disease
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• v.24 no.3
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• pp.213-220
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• 2018

We classified the previously reported antagonistic strains of Sorangium cellulosum into 5 subspecies (A-E). Four strains were antagonistic to Botrytis cinerea (AB group) and two strains were antagonistic to Colletotrichum acutatum (AC group). According to the genetic and sequential analyses with standard genes, xynB1, bglA2, groEL1 for grouping, all strains of AB group were belonged to subspecies C and all strains of AC group were belonged to subspecies D. In addition, high pressure liquid chromatography with the culture filtrates confirmed the genetic results, because AB group had peaks with retention time at 20-22.5 minutes, whereas AC group had no peak. There was positive relationship ($R^2=0.9652$) between the control values of infecting B. cinerea on cherry tomatoes and the main peak areas of chromatograms among the four isolates of AB group. From the subspecies results of AB group, the main peak of KYC 3270 was expected to be epothilone D. However the retention times of the standard of commercial epothilone D and the main peak of KYC 3270 culture filtrate were different as 9.9 and 11.581 min., respectively. Finally, the antagonistic metabolite of AB group was inferred as 7-ketone epothilone D.

• Analytical Science and Technology
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• v.13 no.3
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• pp.269-276
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• 2000

Chromatographic retention mechanism of seven benzoic acids in RPLC were investigated. Inorganic salt is pertinent for the measurement of dead time in benzoic acid. Logarthims of capacity factor (log k') and Hildebrand solubility parameter (${\delta}$) showed proportional relationship which imply the hydrophobic effect of the retention mechanism in RPLC. Enthalpies of solute transfer showed inverse proportion to temperature and organic modifier ratio of the mobile phase. It was found that the S value showed positive slope in plot of log k' vs. volume fraction of water in mobile phase. Free energy change increases with increasing organic volume fraction. The hydrophobicity index, ${\varphi}_0$(organic volume fraction) is inversely proportional to column temperature.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.11a
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• pp.409-410
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• 2000

생물여과 (biofiltration)로 알려진 기술은 오염물을 gas stream이나 liquid stream을 사용하여 생물학적으로 처리할 수 있다. 주요 방법으로 생물세정 방법과 생물여과의 두 방법을 사용하고 있다. 오염물질 제거효율에 영향을 미치는 인자로는 오염물질의 종류와 특징, 오염물질의 유입농도, 충진물의 종류와 형상, 오염물질이 충진물에 머무름 시간 등이 있다. 일반적으로 생물 여과에 있어서 반응기의 충진물로 compost, peat, wood chips와 토양을 이용하거나 또는 활성이 없는 합성 매체를 이용하기도 한다(Leson and Winer, 1991). (중략)

• Korean Journal of Food Science and Technology
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• v.28 no.6
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• pp.1177-1179
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• 1996

A static headspace gas chromatographic (HSGC) technique was used to quantify toluene and other solvents (methanol, isopropyl alcohol, methyl ethyl ketone and ethyl acetate) in food packaging films. Comparison of retention times and coefficient variations for standard solvents showed consistent retention time and good reproducibility. Therefore, this method using static HSGC proved to be superior in rapidity and reproducibility, and is thought to be adaptable to analysis of a large number of samples. The methanol content was $N.D.\;(not\;detected){\sim}0.939\;mg/m^2$, toluene $N.D.{\sim}1.403\;mg/m^2$, melthyl ethyl ketone $N.D.{\sim}0.932\;mg/m^2$, total solvent content was $N.D.{\sim}2.433\;mg/m^2$.

• KSBB Journal
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• v.21 no.3
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• pp.220-223
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• 2006

Lysozyme is an important antibacterial material, as effective food preservative. A number of lysozymes are found in nature such as egg white, where exists about 3.5% of egg proteins. In this study, carboxymethyl cation exchange chromatography has been used for separation of lysozyme. A simulation study by ASPEN was also performed for saving time and cost in chromatography purification experiments. Important parameters in experimental chromatography were sample loading amount, NaCl concentration, and pH of eluent. Simulation results were successfully fitted with chromatograms from experiments with change of parameters mentioned above.